Do human lumbar discs reconstitute after chemonucleolysis? A 7-year follow-up study

Area of Science:

• Orthopedics
• Spinal Surgery
• Regenerative Medicine

Background:

• Animal studies suggest lumbar disc height may reconstitute after chemonucleolysis.
• Human lumbar discs have not shown height recovery within one year post-treatment.
• Long-term human data on disc height changes after chemonucleolysis is lacking.

Purpose of the Study:

• To evaluate the long-term temporal changes in human lumbar disc height after chemonucleolysis.
• To determine if human lumbar discs can reconstitute after chemonucleolysis.
• To assess the healing potential of central disc tissue in humans.

Main Methods:

• A retrospective, longitudinal study of 51 patients undergoing chemonucleolysis with chymopapain.
• Lumbar disc heights were measured via radiographs before treatment, at 4 months, and at a mean of 81 months post-treatment.
• Adjacent untreated discs served as controls in most patients.

Main Results:

• Immediately after chymopapain treatment, treated discs decreased in height by an average of 15.8%.
• No significant height reversal was observed in discs treated with 4000 picokatals (pkat).
• A minor fraction of lost height was regained in discs treated with 3000 pkat; control discs showed a 3.4% height decrease.

Conclusions:

• Human lumbar discs do not demonstrate reconstitution of height after chemonucleolysis.
• The long-term disc height changes in humans differ from animal study findings.
• Caution is advised when extrapolating animal chemonucleolysis results to human disc healing.